XML serialization related problem with XmlIgnore

Question

When serializing a class I get an error if the XmlIgnore attribute is commented. When I uncomment the XmlIgnore attribute it works fine. Can anyone tell me why a property can't be serializable?

Answer 1

Normally, it will tell you why very clearly in the exception - look in particular at the InnerException; however, to summarise:

For a custom type SomeType to be serializable via XmlSerializer (either as the root object or via a property, ie public SomeType MemberName {get;set;} )

• it must be public
• it must have a public parameterless constructor
• a few generic combinations may not be supported
• it must be expected (exposing data as object is a no-go, for example; subtypes of SomeType must be advertised in advance, typically via [XmlInclude(...)] )
• it must be concrete (non- abstract ), or have concrete implementations defined via [XmlInclude(...)]

Using [XmlIgnore] removes the type from consideration, so types that are not xml-friendly can be avoided. You can also try IXmlSerializable for those cases